The United States cannot guarantee that it will provide India with a waiver from sanctions if it purchases major weapons from Russia like the S-400 missile system, a top Pentagon official has said.

Radio Free Europe issued a statement on August 29 by Randall Schriver, the Pentagon's top Asia official. Schriver explained the meaning of Congress passed legislation this month allowing the Pentagon to waive penalties against countries that purchase arms from Russian defence companies that were placed under U.S. sanctions this year.

India was frequently cited as an example of a country that would benefit from the legislation, and media reports in India and the broader South Asia region have suggested that India would get a waiver.

Schriver stated that any expectation to protect India what ever it does is misleading. “I can't sit here and tell you that they would be exempt, that we would use that waiver. That will be the decision of the president if he is faced with a major new platform and capability that India has acquired from Russia,” he said.

U.S. Defence Secretary Jim Mattis has been a strong proponent of granting India waivers. But Schriver said the Pentagon is concerned about India's planned purchase of Russian S-400 surface-to-air missile systems. Russia has said it expects to sign a deal with India later this year on the sale.

US is currently forcing Turkey to give up from its S-400 decision.